notify-mailer: skip invalid contact emails (#4021)

Resolves #4020

cmd/notify-mailer/main.go

@@ -177,7 +177,12 @@ func (m *mailer) resolveDestinations() ([]string, error) {
 			if strings.TrimSpace(email) == "" {
 				continue
 			}
-			contactsList = append(contactsList, email)
+			parsedEmail, err := mail.ParseAddress(email)
+			if err != nil {
+				m.log.Errf("unparseable email for reg ID %d : %q", c.ID, email)
+				continue
+			}
+			contactsList = append(contactsList, parsedEmail.Address)
 		}
 	}
 	return contactsList, nil

cmd/notify-mailer/main_test.go

@@ -338,6 +338,10 @@ func (bs mockEmailResolver) SelectOne(output interface{}, _ string, args ...inte
 			ID:      6,
 			Contact: []byte(`["mailto:mail@example.com"]`),
 		},
+		{
+			ID:      7,
+			Contact: []byte(`["mailto:***********"]`),
+		},
 	}
 
 	// Play the type cast game so that we can dig into the arguments map and get
@@ -391,6 +395,11 @@ func TestResolveEmails(t *testing.T) {
 		{
 			ID: 999,
 		},
+		// This registration ID deliberately returns an invalid email to make sure any
+		// invalid contact info that slipped into the DB once upon a time will be ignored
+		{
+			ID: 7,
+		},
 	}
 	contactsJSON, err := json.Marshal(regs)
 	test.AssertNotError(t, err, "failed to marshal test regs")